Still, the numbers reported in the new study are "quite good," said Dr. Alexander Katalinic, one of the study's coauthors, in an email to Reuters Health.

In the United States, the last time the government-backed U.S. Preventive Services Task Force (USPSTF) looked at the screenings in 2009, the group said there was not enough evidence to recommend full-body exams to check for signs of skin cancer in adults. The USPSTF, however, did not recommend against it either.

Dr. Virginia Moyer, the chair of the USPSTF, said the group reviews its guidelines every few years, and as for now its 2009 recommendation stands.

SOME FALSE POSITIVES

For the study, the researchers examined data from the Skin Cancer Research to Provide Evidence for Effectiveness of Screening in Northern Germany (SCREEN) program, which was conducted in the German state of Schleswig-Holstein between 2003 and 2004. (Germany has had a national skin cancer screening program in place since July 2008.)

More than 360,000 people older than 20 years old and living in the state chose to be screened by doctors who went through a special training to identify suspicious skin lesions or moles.

Some people decided to see a dermatologist while others went to a general practitioner who referred them to a dermatologist if they suspected skin cancer.

Overall, about 16,000 people had a biopsy -- about one for every 23 people who were screened. Doctors identified about 3,100 malignant tumors from those biopsies.

The cost for each screening is about $27. A biopsy can run over $100, and the removal of a malignant skin lesion can cost about $800.

The researchers cannot say how many screenings led to an unnecessary biopsy or treatment, because of the program's design. But, Katalinic said "of course there are false positives."

Overall, there were 3,103 malignant skin tumors, and 585 of those were malignant melanomas, the most deadly type.

More than 50 people between the ages of 20 and 49 years old had to have a biopsy to identify one melanoma. That's more than double the 20 biopsies needed to find one in people over 65 years old.

Katalinic said, as an epidemiologist, he thinks the number needed to screen or biopsied should be improved, especially among younger people. There were also 1961 basal cell carcinomas, 392 squamous cell carcinomas and 165 were other types of malignant tumors.

DID THE SCREENING HELP?

The United States' National Cancer Institute says about two million people in the U.S. are treated for basal cell or squamous cell cancers every year. As for melanomas, the American Cancer Society says more than 76,000 people will be diagnosed with one in 2012 and about 9,000 will die from it.

"The main question is do we find the right skin cancers to prevent deaths and morbidity (or costs)," said Katalinic.

Another study Katalinic coauthored reported that there was a significant drop in deaths from skin cancer following the program.

Deaths from skin cancer fell by about 50 percent -- to one melanoma death or fewer per every 100,000 people each year. The number of deaths from skin cancer in neighboring regions that didn't do screening remained the same over time (see Reuters Health story of May 7, 2012.)

Even that drop, however, could be due to an increased awareness of skin cancer and not the screening itself. The study also didn't look at whether there was a decrease in overall deaths.

"This is terrific information and certainly will be useful," said Moyer of the new study. But, she added, it does not answer the question of whether the screening led to better health outcomes. Also, she said the study could have benefited from a comparison group, who did not get screened.

Moyer said the approach of the SCREEN program may also be a way for the U.S. to solve the problem of there not being enough dermatologists to screen everyone for skin cancer.

Basically, specially trained doctors who are not dermatologists act as gatekeepers and refer patients who have suspicious lesions or moles to dermatologist.

"In terms of feasibility, if it were the case that screening were shown to result in better health outcomes, this would be one possible way to manage that," said Moyer.